For some reason, I laugh to myself whenever I remember this little exchange. When my parents were visiting from Kansas City, my father and I visited the Metropolitan Museum together. While we were looking at paintings by Vermeer, we wanted to talk about that device that some painters use…what was the name of it? I was driven bonkers by the tip-of-the-tongue feeling. I came up with mirabile dictu and tabula rasa before I finally remembered: camera obscura. What a relief.